Acoustic jet engine with flow deflection fluid pumping characteristics



June 25, 1957 e. BODINE, JR

ACOUSTIC JET ENdINE WITH FLOW DEFLECTION FLUID PUMPING CHARACTERISTICSOriginal Filed April 24, 1950 6 Shets-Sheet 1 ELECTQC. MoTOZ I iMAGNE-ro METERI NG VALVE.

- INVENTOR. A4552 7 6 Boo/Ne 4/2,

SOURCE June 25, 1957 A. G. BODINE, JR 2,796,735

ACOUSTIC JET ENGINE WITH FLOW DEFLECTION FLUID PUMPING CHARACTERISTICSOriginal Filed April 24, 1950 6 Sheets-Sheet 2 INVENTOR. ,4LBEE7' 6. fla/Neda SOURCE I l v y I I Juhe 25, 1957 A G. BODINE,

ACOUSTIC JET ENGINE WITH FLOW DEFLECTION FLUID PUMPING CHARACTERISTICSOriginal Filed April 24. 1950 J g-J2.

FUEL. 1/ INJECTOR A5H QECEIVEQ 6 Sheets-Sheet 3 $PARK PLUG INVENTOR. AL8527 G Bap/Ne (/2,

June 25, 1957 BQDINE, JR 2,796,735

ACOUSTIC JET ENGINE WITH FLOW DEFLECTION FLUID PUMPING CHARACTERISTICSOriginal Filed April 24, 1950 6 Sheets-Sheet 4 June 25, 1957 Dm JR2,796,735

ACOUSTIC JET ENGINE WITH FLOW DEFLECTION FLUID PUMPING CHARACTERISTICSOriginal Filed April 24, 1950 6 Sheets-$11661. 5

INVENTOR. 44435176: Eon/Ms (/2.

June 25, 1957 A. e. BODI NE, JR

ACOUSTIC JET ENGINE WITH FLOW DEFLECTION FLUID PUMPING CHARACTERISTICSOriginal Filed April 24. 1950 6 Sheets-Sheet 6 INVENTOR. 445527 6.800/415 Anne/VH6 amplitude.

ited States ACOUSTIC JET ENGENE WITH FLOW 'DE'FLEC- TION FLUID PUMPINGCHARACTERISTICS 1? Ciaims. (Cl. 6039.77)

This invention relates generally to acoustic pulse jet engines,illustratively of the type broadly disclosed in my United States PatentNo. 2,480,626, issued August 30, 1949. This application is acontinuation of, substitute for and consolidation of my co-pendingapplications en titled Acoustic Jet Engine With Centrifugal FluidPumping Characteristics, filed April 24, 1950, Ser. No. 157,740 (nowabandoned), and Acoustic Jet Engine With Flow Deflection Fluid PumpingCharacteristics, filed December 27, 1955, Ser. No. 555,816 (nowabandoned) and is a continuation-in-part of my earlier applicationentitled Multi-Circuit Quarter Wave Pulse let Engine, filed January 12,1948, Ser. No. 1,733, now Patent No. 2,546,966, issued April 3, 1951,connected with the present application by co-pendency through saidapplication Ser. No. 157,740.

Many acoustic pulse jet engines, such as most of those shown in my saidPatent Number 2,480,626, require engine operated check valves in orderto pump their own combustion air. The valveless forms of my acoustic jetengine usually require a blower of ram .air as a source of combustionair. Valves are of course .a source of aero dynamic loss, as well as acause of frequent mechanical failure. Also, the necessity of usingeither auxiliary blowers or ram air is an undesirable restriction.

The general object of the present invention is accordingly the provisionof a valveless acoustic pulse jet engine which pumps or assists pumpingof its own combustion arr.

An acoustic pulse jet engine of the general character to which thepresent invention appertains comprises a resonant acoustic conduit, withfluid inlet and fluid outlet ports (both preferably and usuallyvalveless), together with a sound wave generator means located in theconduit and operable at a resonant frequency thereof to establish aresonant sound wave in the gas body or column in the latter. A velocityanti-node of the standing wave, i. e., a region of maximized gasparticle oscillation velocity, appears in the region of each valvelessport, and a pressure anti-node, i. e., a region of maximized gaspressure oscillation amplitude, appears at the sound wave generatormeans. A large amount of energy exists in the resonant standing wave inthe gas column in the resonant acoustic type engine, being in the formof potential energy at the pressure anti-nodes, alternating twice eachcycle with kinetic energy at the velocity anti-nodes. At the high sonicwave frequency dictated by the natural resonant frequency of the typicalengine, e. g., of the order of 40400 cycles per second, the kineticenergy of the gas at the velocity anti-nodes is of considerablemagnitude and significance. Gas particle acceleration under theseconditions is extremely high, as is maximum velocity The velocityanti-nodes are thus seats of high, maximized kinetic energy, which aredrawn upon in the carrying out of the invention. With the foregoing inmind, a principal .salient feature of the invention in the preferredform thereof is the incorporation of a g-as flow path defining means inthe :conduit in the velocity atent r 2,796,735 Patented June 25, 1957anti-node regions, where the seats of maximized sonic standing wavekinetic energy reside, and at which the air intake and gas dischargeports have been located, such gas flow path defining means so coactingwith the oscillating gas flow that there are produced high gasdeflecting or flow inducing force components directed angularly of thenormal path of free gas oscillation within the velocity anti-node regionof the conduit, viz., inwardly of the air intake port, and outwardly ofthe gas discharge port, under motivation by the velocity anti-nodesseats'of sonic kinetic energy. These force components acting on the gasparticles create pressure gradients within the gas in the conduit, bothacross the gas column in the velocity anti-node regions, and between theinflow and outflow ports, causing a net fluid flow through the ports andthe intervening conduit in response thereto. It will be seen that theflow path defining means at the inlet and outlet ports must bediflerently constructed and arranged relative to the direction of fluidfiow in the conduit thereadjacent, so that the effects of the two willnot cancel one another. Both must aid the desired net fluid flow, or atthe minimum, one must aid, and the other not cancel the first. With thisinnovation, intake and discharge valves, auxiliary blowers, andprovision for ram air, become subject to complete elimination. It mayhere be explained that when I refer to valveless fluid intake and fluiddischarge, 1 have reference to the usual engine operated check valves,either mechanically or differential pressure operated, to be opened andclosed at high frequency, and not to mere throttle valves, which may insome cases be used to advantage in my engine to adjust or regulate thesizes of the intake and discharge orifices.

The engine of the present invention has many uses and forms, including,among others, jet propulsion for aircraft, marine propulsion (usingwater as the fluid medium in the system), as a blower or compressor, andas .a burner to generate heat, power or fluid pressure by combnstion ofa fuel.

The invention will be better understood from the following detaileddescription of various illustrative embodiments thereof, reference forthis purpose being had to th accompanying drawings, in which:

Figure l is a diagrammatic view showing an illustrative form of theinvention; 1

Figure 2 is a cross-sectional view on line 2-2 of Figure 1; 1

Figure 3 is a diagrammatic view showing a modifica- 'tion of theinvention;

Figure 4 is a diagrammatic view showing another modification of theinvention;

Figure-6 is a diagrammatic view showing another modi- 'fication of theinvention;

Figure 7 is adiagrammatic view showing-anothermodification of theinvention;

Figure 8 is a diagrammatic view showing another modification of theinvention;

Figure 9 is a section on line 99 of Figure 8;

Figure 9a is a section similar to Figure 9 but showing a modification;

Figure 10 .is a diagrammatic view showing modified form ofthe invention;

Figure 11 is a diagrammatic modified form of the invention;

Figure 12 is a diagrammatic modified form of the invention;

Figure 13 is ,a diagrammatic modified form of the invention;

Figure 14 is a diagrammatic view modified form of the invention;

Figure 15 is a diagrammatic modified form-of the invention;

another view showing another view showing .another view showing anothershow ng another view showing .another Figure 16 is a diagrammatic viewshowing another modified form of the invention;

Figure 17 is a diagrammatic view showing modified form of the invention;

Fig. 18 is a longitudinal sectional view through a jet engine inaccordance with the invention;

Fig. 19 is a longitudinal sectional view through another embodiment ofthe invention;

Figure 20 is a transverse section taken on line 20-20 of Figure 19;

Figure 21 is a longitudinal sectional view through another jet engine inaccordance with the invention;

Figure 22 is partly in longitudinal section and partly in elevationshowing another embodiment of the invention;

Figure 22a shows a modification of the air intake systernof the engineof-Figure 22; K V

Figure 22b shows a modification of the gas discharge portion of theengine of Figure 22; and l V Fig. 22c is a rear end elevation taken asindicated by the arrows 22!; in Figure 22b.

With reference first to the embodiment of Figures 1 .and 2, numeral 20designates generally an acoustic wave conduit in the form of a hollowring or torus. This conduit may consist of a heat resistant metal pipeformed into a circle, or may be fabricated in any other conventional.rnanner found convenient. The torus 20 has, on its inside or concavesurface, a fluid inlet 21, and it also has, in a position diametricallyopposite from inlet 20, a jfluid outlet 22 connected into its outside orconvex surface.

A sound wave generator means is provided, and while this may takevarious forms, it is preferred to employ a .combustion type, hereindicated as including a fuel intake .pipe 24 and a spark plug 25. Thespark plug 25 is mounted in one side of the torus approximately half way.between the fluid inlet and the fluid outlet, and the fuel intake pipe24 discharges to the interior of the torus somewhat in back of the sparkplug or in other words, between the spark plug and the fluid inlet, soas to provide a fuel combustion zone 26 between the fuel inlet pipe andthe spark plug. The fuel inlet pipe may be regarded as feeding periodiccharges of fuel to the com- 'bustion zone under the control of anysuitable metering device, 'as for example under the controlof a fuelmetering valve 27 operated at a predetermined synchronous speed by anysuitable drive means, as for instance an electric motor indicatedconventionally at 28. As will be 'explained later the electric motor 28is arranged to operate the fuel metering valve 27 at a frequencycorresponding with a resonant frequency of the acoustic cavity formed bythe torus 20. i It ispreferr'ed, and a feature of the embodiment ofFigure 1, that the sound wave generator be duplicated 'on the two sidesof the torus. Accordingly, there is shown in Figure 1, directly acrossfrom the spark plug and fuel feeding provisions already described, afuelfeeding pipe 24a, a spark plug 25a, a combustion zone'26a, a fuel'metering valve. 27:: and an electric motor 28a. The fuel valves 27 and27a are properly synchronized with one another in accordance with theprinciples to be explained hereinafter.

Operationis as follows: Air for combustion enters the torus at 21, andtravels in both directions there'around toward outlet 22 under pumpinginfluences to be presently explained. Charges of fuel are cyclically andalternately introduced to the combustion zones 26 and 26a via the fuelpipes 24 and 24a, thefrequency of fuel charge introduction being aresonant frequency of the sonic cavity "or conduit formed by theltorus.These fuel charges are metered by the valves 27 and 27a, which aredriven at the said resonant frequency by properly controlled andsynchronized electric. motors 28 and 28a. Suitable motors for thispurpose, and suitable synchronizing provisions, are well withintheknowledgeof the art and need not'be explained in detail, it beingsuflicient to note another that the valves 27 and 27a are driven so asto alternately meter fuel charges to the fuel pipes 24 at the resonantfrequency of the circular pipe, the fuel valves being operated at phasedifierence. Any suitable gear reduction means (not indicated) may, ifnecessary, be employed between the synchronously driven valve motors andthe valves.

Combustion is initiated by synchronously operated spark plugs 25 and25a,'which are also cyclically energized to spark alternately, with 180phase diflerence. These spark plugs are of course energized just afterthe fuel introduction, and it will be understood that any suitableignition system may be employed, but that the same must be properlysynchronized with the fuel metering valves 27 and 27a. For example, thesame motors that drive the fuel metering valves 28 and 28a may alsodrive magnetos 29 and 29a, connected to the respective spark plugs. Withmany fuels it has been found that a lingering tail-flame can bemaintained, after each combustion cycle, behind the turbulence baffles30 and 3011.

Each new charge is then ignited by the tail-flame; and the spark plugsarein such cases necessary only for starting.

Assume first a fuel explosion at combustion chamber region 26 resultingfrom ignition by plug 25 of a fuel charge introduced via supply pipe 24.Such explosion initiates a pressure pulse, which starts waves ofcompression traveling with the speed of sound in the gases in bothdirections around torus 20. These two oppositely traveling compressionwaves meet on the opposite side of the torus to create a pressure peakat zone P, whence they are reflected and return in reverse directions,again around opposite sides of the torus, to meet again at their pointof origin, designated P, to create a pressure peak at that point. Thezones Pand P are not diametrically opposite since the wave travelsfaster in the hot gases downstream from combustion than it does in thecold intake air. The fuel feeding system is so timed that a new fuelcharge is'introduced at 24 just prior to vthe meeting of these waves,and the said pressure peak compresses this charge, whereupon, at thetime of the said pressure peak at P, the spark plug is again energized,or the compressed charge becomes ignited by the previously mentionedtail-flame, to explode the second fuel charge, whence the cycle isrepeated;

Assuming a fuel explosion at zone P coincident with each pressure peakat P, pressure anti-nodes (zones of maximum fluid pressure variation)will appear at zones P and P,.and will hereinafter be designated by saidcharacters. Halfway between said pressure anti-nodes, at the locationsof the inlet 21 and outlet 22, will be velocity anti-nodes V and V(zones of maximum fiuid velocity variation). An acoustic standing waveis thus established aroundthe torus, with velocity anti-node zones VandV at inlet 21 and outlet 22, respectively, and with a pressureanti-node P in the upper half of the torus, at combustion zone 26, and apressure anti-node P in the lower half of the torus, locatedsymmetrically with reference to pressure anti-node P. It will be seenthat with such timing of the combustion system, the

torus is a half wave in length from the zone P around to ployed, fuelcharges willbe ignited 180 of the cycle out of phase with respect to,the explosions produced at combustion zone 26, and it will be seen thatthe cyclical explosions so caused at combustion zone 26a will be timedto occur coincidently with the pressure peaks appearing at zone P as aresult of the explosions produced at zone 26. The power of the system isthus doubled, and

an increased strength standing wave is gained, but the nature of thestanding wave is not altered.

Considering now the fluid velocity zones V and V, it

will be evident that following an explosion say at combustion zone P,fluid will move at relatively high velocity in left handed and righthanded directions, respectively, through the velocity anti-node zones Vand V, reaching peaks of velocity 90 in time of the cycle following theexplosion. The fluid Velocity then falls towards zero as the pressure atP is built up, reaching its minimum coincidently with the pressure peakat P, which event occurs 90 following the time of velocity peaks at Vand V. The gas flow then reverses direction through the Zones V and V,reaching maximum velocity in this back flow within another 90 of thecycle, after which the velocity decreases as the new pressure peak isouilt up at P. These high alternating velocities in the region V can be,in some cases, enough in themselves to cause periodic introduction ofthe fuel to the combustion; thus making possible the elimination of theperiodic valves 27 and 27a in the fuel lines, and allowing the use ofsteady flow of fuel into the intake section.

Very high fluid velocity is thus achieved through the curved zones V andV of the torus twice during each cycle of the wave, and may reach oreven somewhat exceed the velocity of sound. Owing to the curvature ofthe zones V and V, and the consequent inward deflection of the fluid bythe outer peripheral walls of the torus,

very substantial centrifugal forces are set up in the fluid, causing itto be crowded radially outward the outer peripheral walls, and therebyestablishing a substantial pressure diiferential in a radial directionacross the torus at zones V and V. This pressure differential creates apressure depression at the inner wall, and hence at air inlet 21, withthe result that outside air is sucked into the system through 21. Thispressure differential also creates an elevated pressure at the outerwall, and hence at outlet 22, so that fluid in the system is dischargedat 22. Moreover, a pressure gradient is created through the conduitbetween the inlet and the outlet. Fluid is thus pumped through thesystem, in at 21, and out at 22, by the combined action of the standingwave set up in the system and the development of flow inducingcentrifugal forces, as a result of causing the fluid particles moved bythe standing wave to change their direction adjacent the fluid inlet andthe fluid outlet, the change of direction, or deflection, and thelocation and orientation of the inlet and outlet, being such as todevelop forces which will be in aid of the inflow at 21 and in aid ofthe outflow at 22. It will be clear that, broadly, inflow and outflowfluid path defining configurations have been provided which aredifferently arranged relatively to the direction of fluid flow in thevelocity anti-node regions of the conduit, furnishing an overallpressure gradient that produces a net fluid flow through the conduit.Net pumping of air through the system is thus achieved without use ofvalves.

Figure 3 shows a modification of Figures 1 and 2, wherein the conduit 2%is interrupted at the lower pressure anti-node zone and provided withrigid end closure reflecting walls 34 and 35. Also, in this embodiment,but one wave generator means is employed, namely, the one located at theupper pressure anti-node P, and shown again .to consist of a fuel supplypipe 24b and a spark plug 25b. Otherwise, the system may be the same asthat of Figures 1 and 2, and corresponding reference numerals areaccordingly employed for similar parts, but with the suflix b added inthe case of Figure 3.

Operation of the system of Figure 3 is exactly like that of Figure l,the only difference being that simultaneous pressure anti-nodes P and P"exist adjacent the closure walls 34 and 35, in place of the singlepressure anti-node P when the conduit is in the form of a complete ringor torus. Thus velocity anti-nodes exist at V and V as before, and thesame type of standing wave is established, resulting in the developmentof the centrifugal forces which pump the fluid in at the inlet and outat the outlet.

Attention is particularly called at this time to the fact that in theembodiments of Figures 1-3, the inlet is on.

Figure 4replaced by a quarter-wave .pipe section.

an inside or concave curve, while the outlet is on an out side or-convexcurve, thereby affording maximum benefit from the centrifugal forcecomponents developed as described in the regions V and V. In certainlater described embodiments there is some departure from thisarrangement, but operation in accordance with the invention is stillachieved, as will appear.

Reference is next directed to Figure 4, showing diagrammatically asimplified quarter-wave version of the invention. In this instance thereis provided a curved sonic pipe 44 having an open end 41, and equippedat its other end position with an acoustic wave generator means 42,which in this example is simply in the form of a piston 44 fitted forreciprocation with a close sliding fit in pipe 40, and driven throughconnecting rod 45 and crank 46 from any source of speed-controlled andsynchronized rotary power, such as electric motor or engine 47. It willbe understood that this motor or engine must be synchronized to drivepiston 44 at an oscillation frequency which is a resonant frequency ofthe open-ended pipe 41), so as to establish a standing wave in the pipe,with a velocity anti-node V adjacent the open end and a pressureanti-node P adjacent the piston. Curved pipe 40 has also, near or withinvelocity anti-node region, fluid intake opening 48 and fluid dischargeopening 49, the former located on a longitudinally concave externalcurve of the pipe, and the latter on a longitudinally convex externalcurve of the pipe.

In the operation of the apparatus of Figure 4, fluid rushes back andforth through the velocity anti-node region V, and as a result of thecurvature of the pipe, is deflected so as to set up centrifugal forcecomponents as before, which in turn create a pressure differentialacross the velocity anti-node region, with a minimum pressure adjacentthe inside periphery of the pipe, and a maximum pressure adjacent theoutside periphery thereof. This differential pressure condition sucks inoutside fluid at 48, and discharges internal fluid at 49, thus pumpingfluid through the system by the development of centrifugal forces underacoustic standing wave drive.

It may here be noted that many of the systems disclosed herein,particularly when equipped with a piston drive means, as in Figure 4,are adapted for pumping of water as well as gaseous fluids, and mayhence be employed for marine propulsion. In any such case, thepropulsive effect described herein is of course'achieved by virtue ofthe jet discharge at 49.

In Figure 5 is shown a system similar to Figure 4, but avoiding the openend of thesonic pipe. For convenience, corresponding parts in theembodiments of Figures 4 and 5 are identified by the same referencenumerals, but with the suflix a added in the case of Figure 5. As willbe seen, the sonic pipe in this instance,.instead of terminating in anopen end, has beyond fluid inlet 48a and fluid outlet 49a, a short pipesection 50 terminating in a capacitance chamber 51, the acousticinductive reactance of the pipe section or neck 50 being balancedagainst the acoustic capacitance reactance of chamber 51 to produce acondition of effectively zero impedance at the junction with the sonicpipe. This zero impedance combination of acoustic elements thus replacesthe open pipeend 41 of the embodiment of Figure 4, while giving the samestanding wave conditions in the pipe. Thus, the apparatusof Figure 5operates to produce a standing wave characterized by pressure anti-nodeP adjacent piston 44a and velocity anti-node V in the region of inlet48a and outlet 49a. Pumping of fluid inward through 48a and outwardthrough 49a is accomplished in exactly the same way as previouslydescribed in connection with Figure 4.

Reference is next directed'to Figure 6, showing a system similar toFigure 4, but with the open end .41 of In Figure 6, parts correspondingto parts in Figure v4 are indicated by similar reference numerals butwith "the sufiix '1: added. Pipe 46b thus'has, in lieuof the openlongitudinal edges from the'sides of the pipe.

ensues 7 v end 41, a quarter-wave extension 54, which may be curved likethe pipe 40 of Figure 4, so that the whole forms substantially a halfturn, with fluid inlet 48b on the inside periphery of the pipe, halfwayalong the length thereof, and with fluid outlet 4% on the outsideperiphery 'of the pipe, halfway along the length of the pipe. In thiscase, operation is similar to that accomplished in Figure 4, in that apressure anti-node P appears adjacent piston 44b (assuming of courseresonant oscillation of said piston by its power source), a velocityanti-node appears at V, in the region of inlet 48b and outlet 4%, and asecond pressure anti-node P appears at the end of the curved leg 54. Asin the other embodiments of the invention, the fluid oscillating backand forth, in the pipe in the region of velocity anti-node V is subjectto centrifugal force creating a pressure diflerential across the pipewhich results in fluid inflow at 48b and fluid outflow at 491).

Figure 7 shows a further modification, characterized by the use of asonic conduit 60 forming a half circle, i. e., of 180 angular extension,this conduit having midway of its length and on its inside periphery afluid inlet 61, and having midway of its length, but on its outsideperiphery a fluid outlet 62. In addition, the pipe 60 has a transversepartition Wall 63 extending from a point just short of piston 440 to apoint a short distance beyond the fluid inlet 61 and fluid outlet 62. Inoperation, piston 440 is driven at a resonant frequency of the pipe 60,so as to create pressure anti-node conditions P and P at the two ends ofthe pipe, and a velocity anti-node condition midway of the pipe adjacentthe inlet 61 and below the partition wall 63, as indicated at V1 andalso a velocity anti-node condition V2 on the opposite side of thepartition wall 63, in the region of outlet 62. In efiect, the partition63 divides the one leg of pipe 60 (the right hand leg as viewed in thefigure) into two pipes connected at P and having velocity anti-nodes V1and V2 at the ends remote from such connection. The left hand leg of thepipe, on the other hand, is a' quarter wave in length, and consistssimply of a single undivided pipe, as will be clear. In operation, thefluid oscillating back and forth at the velocity anti-node regions V1and V2 set up centrifugal forces which induce inflow of air inwardlythrough i 61 and outwardly through 62;

With reference next to Figure 8, the apparatus will be seen to be thesame as in Figure 7, with the exception that the partition wall 63aextends around and through the left hand leg of the pipe, almost to theend of the latter. Here conditions are actually much similar to thosefound in Figure 7, the exception being the clear and complete separationof the velocity anti-node region V1, from the velocity anti-node regionV2. In the final effect, however, the behavior of the system isessentially that of the earlier described embodiments. The inflow fluidoscillating at region V1 of course travels closely adjacent thepartition wall 630, rather than adjacent the outside peripheral wall ofthe apparatus, so that a pressure differential is created between theconcave inside wall of the apparatus and the partition wall 63a, thusproviding the necessary pressure depression at the inlet to secure thedesired suction. Figures 7 and 8 taken together are primarilyinteresting in that they show how the half wave type of pipe shown inFigure 6 may be increased in effective length to provide three quarterwave pipe lengths in Figure 7, or two half wave lengths as in Figure 8.Essentially, the embodiment of Figure 8 does not differ from theoriginal embodiments of Figure l.

Figure 9a is of further interest in that it shows a modifiedcross-section of Figure 8 wherein the partition wall, this timeindicated by numeral 63b, is'spaced along its Such construction willpermit a small amount of flow from one side of the partition to theother, but will not afiect the essential operation of the system. Inother words, the embodiments of Figures 6 and 8, with the latter havingeither the section shown in Figure 9 or the section shown in Figure 9a,are essentially equivalent.

It will be noted that the partitions of Figures 7 or 8 cause part of theinflow to pass through a pressure antinode zone. This permitsmaintenance of combustion at the pressure anti-node so that theapparatus can be driven similarly to Figure 1. Figure 6, on the otherhand, is limited to piston drive because intake air flows almostdirectly across to discharge opening 49b.

The embodiment of Figure 10 consists of two semicircular pipe lengthsand 71, having two corresponding ends interconnected by a chamber 72 inwhich is located resonant sound wave generator 73., In the presentinstance, this generator 73 comprises a piston 74 driven from asynchronized power source 75 in a way previously indicated in connectionwith other figures, so as to resonate the two pipe lengths 70 and 71 andestablish standing waves therein. Each pipe length 70 and 71 is a halfwave in length, and it results that there is created in chamber 72 apressure anti-node P, at the far end of pipe 71 a pressure anti-node P".Velocity anti-node regions V and V are established at the midpointregions of the two pipes 70 and 71, as indicated. Opening into insidewall of pipe 70, adjacent velocity anti-node V, is fluid inlet 77, andopening from the outside wall of pipe 71, opposite velocity anti-noderegion V, is outlet 78. While for convenience of illustration, the twopipes 70 and 71 are in a single plane, it will become evident that thisis not necessary, and the pipes may be in planes at right angles to oneanother, parallel to one another, or in any other relationship foundconvenient. The operation of the apparatus of Figure 10 is again likethat of Figure 8, or indeed like that of Figure 3, standing waves ofsimilar character being established in each case, and there being ineach case an effective pipe length of a total of one wavelength withpressure and velocity anti-nodes distributed in equivalent positions.Considering Figure 10 in more particular, it will be seen that thepiston 73 will send pressure pulses along the lengths of both of thepipes 70 and 71, and that these pressure pulses, after reflection fromthe ends of the two pipes, will return to the pressure anti-node regionP in chamber 72 coincidently with the next pressure pulse, and so on, ina manner such as will establish the described standing wave andconditions as already described. The fluid flow in the velocityanti-node regions of the two curved pipes 70 and 71 will again besubject to centrifugal forces which will develop an inflow suction at 77and an outflow discharge'pressure at 78. It can be seen that combustiondrive of the wave can be substituted for the piston 73 because intakeair flows through region P, from V to V.

With attention now to Figure 11, an apparatus is disclosed having againtwo interconnected half wave pipe sections 80 and 81, which sections maybe in the same plane, or different planes. A cylinder 82 fitted with apiston 83 communicates with the junction point of the two pipe sections,and is driven from power source 84 at a synchronous speed to resonatethe fluid in the two pipes. Standing waves accordingly appear, and thesewill be equivalent to those previously considered in connection withFigure 10 and other figures, having a pressure antinode region P at thejuncture of the two pipes 80 and 81,

pressure anti-nodes P and P at the far ends of the two pipes 80 and 81,and velocity anti-node regions V and V midway of the length of the twopipe sections 80 and 81. A fluid inlet 86 opens through the insidecurved wall of pipe 80 in the region of velocity anti-node V, and afluid outlet 87 opens through the outside curved wall of pipe section 81in the region of velocity anti-node V. The oscillating gas flow in thetwo regions V and V' will again develop centrifugal forces establishinginflow at 86 and outflow at 87.

It will be noted that in all of the exemplifications of the inventiondescribed in the foregoing, the fluid inletis on an inside curve,whereas the fluid outlet in on an out= on a sharper curve than is theinlet 2112.

side curve. There are certain embodiments of theinvention which do nothave this feature, and a few exemplifieationsof these will now bediscussed.

Figure 12 thus show an embodiment of the invention similar to Figure 3,but with half of the torus of Figure '6 added in the case of Figure 12.It should be evident thata standing wave may be established in thesystem of Figure 12 the same as in Figure 3, with a pressure anti-node,P at the combusfion zone, pressure anti-nodes 'P and P" at the two endsof the pipe, 'and'velocity'antinodes V and V, in the regions of thefluid inlet 21c and fluid outlet 220, respectively. Operation of theapparatus of Figure 12 will be 'similarto'that of Figure 3, with theexception that no centrifugal force effects occur in the straightenedleg of the pipe. Nevertheless, because of the centrifugal force effectsat velocity anti-"node region V,sufiicient pressure differential isinduced to etfect'pump ing-offluid in at 21c and out at 22c.

Figure "13 indicates simply the reverse arrangement of Figure 12, wherethe other half 'of-the ring of Figure 3 has been formed as astraightened leg. Otherwise, the parts are exactly similar to Figure 12,and corresponding members are indicated by corresponding referencenumerals but with the suflix d employed in the case of Figure 13. Here,centrifugal force efiects take place at V'to induce inflow into thesystem, but there are no centrifugal force effects at region V to assistin discharge of fluid. However, the centrifugal force effects at regionV are suflicient to establish a pressure differential which will pumpfluid through the system, inward at 21d, and out at 22d.

Figures 14 and 15 show two further exemplifications of the invention, inthe first of which'the fluid inlet 21e opens into a convex or outsidecurve of the pipe, the same as does fluid outlet 222, and in the secondof which, the fluid outlet 22 leads from a concave or inside curve ofthe pipe, the same as does fluid inlet 21 Otherwise, the embodiments ofFigures 14 and 15 are similar to Figure 3, and corresponding parts areidentified by corresponding reference numerals but withthe suflixes eand 'f employed in thecase of Figures '14 and 15, respectively.

Figure 15 shows additionally optional outlets 227' and 90, useful forsome purposes presently to be mentioned, but these may be disregardedfor the present.

It wil be evident, referring to theem'bodime'nt of Figure 14, that theinduction of air on a convex curve of the pipe will be opposed by thecentrifugal force eflfective on the fluid stream within the pipe at thatregion. It will likewise be evident, referring to the embodiment ofFigure 15, that discharge of fluid from the concave side of the pipe, asat 22 will be opposed by prevailing centrifugal force efiects on thefluid stream in the pipe. However, both the embodiments of Figures 14and 15 are made operative by having the curvature of the pipe greater inthe velocity anti-node region where centrifugal force efiects arefavorable than they are at the velocity anti-node region where theeffects of centrifugal force are unfavorable. Thus, in Figure 14, :theoutlet 22e is Hence, centrifugal force effects will be greater in theoscillating fluid at the region V than at the region V, and a pressuredifferential will hence exist between the inlet and the outlet, causingpumping of fluid to occur through the system. In the case of Figure '15,fluid inlet 21f-is on a sharper curve than is fluid outlet 22 so thatthe centrifugal force eflects in the region V will predominate over theunfavorable centrifugal force eflects in the region V; hence, a pressuredifferential will occur between the inlet and outlet, and fluidwillagain be-pumped through the system. The word curvature, as used inthe claims and elsewhere, is intended to include all physi- 10calmeanings .of deflection, including sharpangles or bends.

One of the best uses for this invention is as ahigh e'fliciency burner,such as for the combustor section of a gas turbine. Actual test haveshown surprisingly high efficiency for a combustion process whenoccurring in a self-excited acoustic field. Pulverized coal can beburned with extremely high completeness of combustion in a very compactsonic burner. And the self-pumping characteristic of this invention isthen an additional benefitin flowing the combustion air.

Another use of thecentrifugal effect made possible'by this invention ithe centrifuging action on materials of different densities. Referringto Figure 15 we can see a plurality of discharge openings located at theanti-node zone V. It will be evident that, recognizing a radialcentrifugal field at V due to deflected anti-node oscillations, theheavier components of the fluid will tend to crowd to the outside of thecurve. And the lighter material can be discharged from intermediateopening 22 with the lightest being available at opening 22). Whenburning coal this feature is a special benefit because, by sacrificingsome pumping effect with a gas discharge such a 22f or 22], the highercentrifugal point at the entrance to pipe can be used for ash removal.The ashes can be collected in receiver 91.

In consideration of the many possible uses for the acoustically drivencentrifugal effect of this invention it is accordingly the intent thatthe element identified as either the intake or discharge opening, in theclaims and elsewhere, is to be considered in the broad sense of astrategically located opening utilizing some benefit from anacoustically driven propelling or jetting effect.

Figure 16 shows a multi-stage form of the apparatus, based on theembodiment of Figure l. The inner torus of Figure 16 may be preciselylike that of Figure 1 and may contain the same sound wave excitationsource, as indicated. In addition, however, it is shown with optionalauxiliary air intake pipe 96, located on the inside, and diametricallyacross from intake pipe 21. For convenience, parts of Figure 16corresponding with parts of Figure 1 are identified by the samereference characters, but with the use of primes in the case of Figure16. Surrounding torus 20 'is a larger torus 100, which may otherwise beof a character identical to that of torus 20', and may be provided withspark plugs 101 and Mia, and fuel intake pipes 102 and 102a. Theprovisions for feed ing fuel to the fuel supply pipe, as well asenergizing the spark plugs, are for simplicity omitted from Figure 16but may be of the same character as previously described in connectionwith Figure l. The air intake for torus I00 consists of a short lengthof pipe 106 leading from the outside periphery of torus 20' to theinside periphery of torus in the region of the air intake 21' for theinside torus 20'. The fluid discharge outlet 22 for torus '20 may simplydischarge separately, or may, if desired, open into the inside peripheryof torus 19a), and the latter has, daimetrically across from its intakepipe 106, an outlet 108 leading from its outer periphery. An additionaltorus might be added around the outside of torus 100, and so on, to anynumber found feasible in practice. The pipe 106 is the necessaryinterconnection because it is via this path that boosted intake air issupplied to each successive torus. The interconnection 22' is thusoptional.

Considering the operation of the apparatus of Figure 16, it will be seenthat the intake air flowing in through intake 21' will be set intooscillation at velocity anti-node region V, and centrifugal force effectdeveloped in this oscillating fluid will cause a portion of the same tobe delivered via pipe 106 to the intake of outside torus 100. It will beseen that this air so delivered from the inner to the outer torus willarrive within the latter at an initial pressure, the inside torus thusfunctioning as a supercharger.

Exhaust fluid delivered from torus 20"through outlet arsenals 1.1 pipe22' enters torus 100, to be delivered with the outflow from 'the lattervia the discharge outlet 108.

It willpf course be understood that the outside torus 100 will functionjust as does the inside member setting up pressure anti-node conditionsP1 and P2, and velocity anti-node conditions V1 and V2, as indicated.Fluid discharging from torus 20 via pipe 22' into torus 100 will beadded to the oscillating fluid in the region V2 of the latter,increasing the pressure level accordingly, and the combined gases willbe discharged by reason of the centrifugal force effects as well as theelevated pressure conditions by way of the final discharge outlet 108."In this way, by a multi-stage process, a very great pressuredifferential can be built up between the air intake ofthe first torusand the discharge outlet of the last toms of the multi-stage group. Theoperating wave cycles of the two or more multi-stage separate units canhave any desired interrelated phasing.

The high average pressures in the outer torus permit 7 large acousticpressure amplitude with resulting large pressure changes, thus causinghigh expansion ratio with *restflting high efliciency of transfer ofheat into wave energy during the combustion process at P1 and P2. Thesehigh pressures and high thermal efficiencies are especially valuable forhigh velocity jets and for high efiiciency gas turbines.

It is possible to reduce the secondary loss of energy from the system bypipes 21, 96 and 108 provided they are sufficiently long to produce aproper acoustic impedance for wave energy at the junction with thetorus. I

have also found that there is usually a best length for pipes 22' and166. Adjustable throttle valves t, t and t", such as shown in pipes 21,96 and 108 can be used to control the power rate of the system. Theseaccessory pipe and throttle features are also equally usable on manyother embodiments of my invention.

Fig. 17 shows another embodiment of the invention, and in which numeral120 designates a U-shaped sonic pipe, comprising legs 121 and 122connected by semicircular pipe section 123, the latter having, openingfrom the midpoint of its convex side, fluid discharge outlet or tailpipe 124. Synchronized acoustic wave generator means are employed inconnection'with the closed ends of the two legs 121 and 122, and as hereshown these means are of the cyclical combustion type. Thus, the:two'legs are equipped adjacent their closed ends with spark plugs 126and 127, and while no means for energizing these is shown in Fig. 17, itis to be understood that these may be energized in proper synchronousrelation, 180 out of phase with one another, by any suitablesynchronized ignition system, for instance of the type shown in Fig. lof the present application. An alternative is indicated in Fig. 2 of myaforesaid Patent No. 2,546,966. Fuel feeding means of the type shown inFig. 1 might be employed, and may be considered as an alternative, but Ishow in this instance carburetors 130 and 131 in conjunction with airinduction pipes 132 and 133, respectively, the latter opening into thelegs 121 and 122 near the closed ends of the latter. The two closed endportions of the legs 121 and 122 form combustion chambers 133 and 134,respectively, the combustion mixture of fuel and air entering throughpipes 132 and 133 reaching these combustion zones and being ignited bythe spark plugs 126 and 127. By energizing the spark plugs cyclically,in 180 opposition, each at the resonant frequency of the pipe 120, or byrelying upon tail-flame ignition, the fuel charges are explodedalternately in such way as to send pressure pulses alternately from oneend of the U tube to the other, the resonant occurrence of theexplosions causing a standing wave to be established in the pipe withpressure anti-nodes P and P at the two combustion zones, and with avelocity anti-node V in the pipe adjacent the outlet 124. 7

One substantial difference between the embodiment of Fig. 17 and thoseearlier described will be noted in that the air intake into the main gascolumn is at a pressure anti-node zone rather than at a velocityanti-node zone. This'is made possible by employing induction pipes 132and 1330f high acoustic impedance. Pipes of quarter wavelength for theresonant frequency of the wave generated in the U-tube will serve thepurpose. For a more complete explanation of the phenomena hereinvolved,reference should be had to my Patent No. 2,731,795, issued January 24,1956. As there explained, a valveiess air intake to a pressure anti-nodezone may be employed provided the air intake pipe has a sufficientlyhigh acoustic impedance, so as to prevent loss of standing wave energyfrom the pressure anti-node zone through said intake pipe.

In the operation of apparatus of Fig. 17, therefore, fuel and airmixture enters the two combustion chambers via the two induction pipes132 and 133 and these mixtures are alternately exploded to establish thestanding wave already explained. At the velocity anti-node region V,products of combustion oscillate back and forth around the curved pipesection at maximized velocity and at resonant frequency, and centrifugalforce effects crowd these oscillating gases toward the outer side of thecurved pipe section. There, the oscillating gases encounter the sharpannular edge 136 formed at the intersection of the flaring tail pipe 124and the sonic pipe 120. Preferably, the sides of the flaring tail pipe124 make an acute angle with sonic pipe 120, so as to form a somewhatsharpened annular edge 136. These sharp edge configurations formed inthe pipe walls at the velocity anti-node region intercept a largeportion of the oscillating gas particles crowded by centrifugal forcetoward the outer wall of the curved pipe section 123, and deflect thesame into the tail pipe 124, to be discharged to atmosphere. The edgesthus provide a deflector configuration which intercepts a portion of theoscillating gases at the velocity anti-node region, and thence deflectsthe intercepted gases to final discharge.

Attention is called to the fact that in the case of the engine of Fig.17, the gases are forced out the tail pipe by two separate forceelfects, both motivated by "the kinetic .energy of the oscillating gasesof the velocity anti-node.

One eflect is that of centrifugal force, owing to the outer wall of theconduit being longitudinally curved or deflected in the region of thedischarge port, which causes some of the oscillating gas particles to becorrespondingly deflected, and therefore to crowd outward and so passthrough the tail pipe. The second effect is that owing to some of theoscillating gas particles being intercepted and deflected outward(peeled-off) by the sharp edge 136 at the junction of the conduit withthe flaring tail pipe. It will be seen that the high velocity gasparticles intercepted and deflected outward by these cavity wallconfigurations are, in this case also, forced out the tail pipe by forcecomponents motivated by the kinetic energy of the oscillating gasparticles of the velocity anti-node.

It will be noted that there are no flow inducing force effects at theair intake portions of the apparatus of Fig. 17. However, the provisionfor force-induced discharge creates the necessary pressure gradient ordiflerential between the discharge outlet and intake pipe, and airv isaccordingly pumped through the system without. the necessity of blowers.Of course, assuming a jet propulsion application of the invention, andassuming also that the an induction pipesl32 and 133 are provided withforwardly facing air scoops, as indicated at 140 in Fig. '17, air willenter the system through the two pipes 1.32 and 133 under ram pressure.The flow inducing force effects gained at the velocity anti-node regionV would then augment the discharge pressure, not being indispensable 'topumping of air through the system, but very greatly aiding the pumpingeffect, and hence the effectiveness of 'thesystem. J v Many of thedisclosed forms of my jet engine provide a means for intercepting anddischarging a portion of the oscillating gases at a velocity anti-nodewhich is located between two pressure anti-nodes. Reverse flow throughthe discharge port back into the system is in each case reduced on thereverse flow half-cycle at the velocity anti-node region by the pressurewithin the velocity antinode region of reverse flowing internal gases.Reverse flow into the system being thus curtailed, a net pumping actionis set up through the discharge port. Moreover, the system retainswithin it the necessary gas to support the desired pressure cycle, andthe operation of the system is thus made independent of reverse flow gassucked in through the discharge outlet on alternate half-cycles. Theinvention will be seen to involve the broad generic concept ofgenerating a pumping force in a fluid by defleeting oscillating gas flowin a resonant acoustic wave guide at a velocity anti-node, making use ofthe seat of kinetic energy at the velocity anti-node to motivate theaction.

With reference now to the embodiment of Fig. 18,

numeral 169 designates generally a gas conduit or pipe, of generallycylindrical form, having a head end portion 161, into which opens avalveless fuel and air intake pipe 162, the latter having an air scoop163 at its forward end. The rearward end of pipe 169 is flared or formedwith a skirt portion, as indicated at 164, and received within thisskirt portion, an annularly spaced therefrom, is a convergent forwardend portion 165 of a conduit or pipe extension 166, provided with aclosure 167 at its far end, the portion 165 forming a gas deflectingwall element. The skirt portion 164 of pipe 169 and the convergentportion or gas deflector 165 of pipe 166 are connected, as by means ofwebs 168, leaving an annular gas passage 169 for discharge of productsof combustion. As will be seen, the convergent portion 165 of pipe 166terminates at its forward end in an annular edge 171 spaced inside thepipe 160, and in a position to intercept a portion of the oscillatinggas particles traveling from left to right at the juncture of the pipes169 and 166. As will be seen, the portion of this gas intercepted by theedge 17!) is deflected into the annular gas discharge passage 169 and sodischarged to atmosphere in a generally outward and rearward direction.

The head end region 172 of pipe 169 forms a combustion zone, whereinfuel, supplied to intake pipe 162 as by carburetor 173, together withair taken in by scoop 163 and supplied to region 172 by the pipe 162,are periodically burned. To initiate combustion, a spark plug 174 isemployed, energized by any suitable ignition system, not necessary toillustrate herein.

The pipe sections 161) and 166, taken together, form a half-wavelengthresonant acoustic pipe, the sections 160 and 166 being each ofone-quarter wavelength. The operation of both quarter wave and half waveresonant engines is understood in the art, and it will be understood howexplosions taking place at the combustion region 172 at the resonantfrequency of members 160 and 166 set up an acoustic standing Waveaction, producing a pressure anti-node P at the combustion region, and avelocity antinode V at the end of pipe section 1643. Pipe section 166 isof the same effective length as pipe section 166, and accordingly, apressure anti-node P is established at the closed end of pipe section166. Under these circumstances, periodic pressure pulses, at theresonant frequency of the pipe sections, are developed by intermittentcombustion at Zone 172, causing periodic pressure peals at regions P andP, and oscillating gas flow longitudinally of the pipe sections 169 and166 at region V.

The valveless air intake pipe 162 is made of substantially quarterwavelength for the resonant frequency of the pipe sections 16%) and 166,or at least is designed for high acoustic impedance for the resonantfrequency of the pipe sections 160 and 166, as explained hereinabove inconnection with Fig. 17.

The overall operation of the engine of Fig. 18 is as follows: Air iscontinuously supplied to the combustion region 172 through pipe .162,and fuel is supplied by car? buretor 173. Operation .is initiated bymeans of spark plug 174, which maybe energized by any suitable ignitionsystem at the resonant frequency of the pipe 160. Explosion taking placeat 172 generates a pressure pulse, which sets up a pressure wavetraveling longitudinally of the gas column in the pipe sect-ions and 166with the speed of sound. Reaching the far end 167, a half-cycle later,this wave is reflected and returned longitudinally towards the head end161. At this same instant, the pressure at the head end 161 is at anegative pressure maximum. The wave reflected from 167 reaches head end161 a half-cycle later, and a positive pressure peak is experiencedthereat. At this instant, a negative pressure maximum is experiencedadjacent end 167. The reverse traveling positive pressure wave (from 167to 161) is refiected from 161, and at the same instant, a secondexplosion occurs at 172, producing a re-enforced positive pressure pulseor wave which then travels longitudinally of the pipe sections 160 and166 in the original direction (from 161 to 167). The gas at velocityanti-node V travels first in one direction, and then the other, reachingmaximum flow velocity as the described traveling :waves pass through it,and reaching zero velocity during pressure peaks at P and P. Thus thereis established a halfwave length standing wave, with pressure anti-nodesat P and P, and a velocity anti-node at V.

After operation has once been started, the ignition system energizingspark plug 174 may be disconnected, since an after-flame retained in theregion 172 is sufficient to ignite the fuel on each positive pressurepeak of the standing wave occurring at region 172. As a result of theacoustic standing wave action, the region V, as already mentioned, isone of high velocity alternating gas oscillation, the gas traveling inreverse directions on a lternate half cycles of the standing wave, asexplained, and as indicated by the arrows. The annular edge 170 acts toskim or pea l off an outer annular layer of the oscillating gas columnon every alternate half cycle (the half cycle wherein the gas flow isfrom P to V) in the general region identified by the letter V, and thisintercepted gas is deflected outwardly and rearwar'dly through theannular opening 169, as indicated by the arrows. The velocity anti-nodeV will again be seen to be the seat of kinetic energy drawn upon tomotivate lateral deflection of some of the oscillating gases, and henceto establish the desired net pumping action through the engine.

' The center portion of the oscillating gas column at the zone V, notpeeled off by the annular scoop or deflecting wall continues itsrearward motion, in the direction of P, and the wave action in thecolumn then builds up a momentary pressure peak at P. The wave isthereupon reflected from P, to cause a forwardly flowing gas columnmotion at V, occurring one half-cycle after the rearward motion. Thisgas column motion from extension 166 back into pipe 161) supplies theneeds of the pipe 161) to maintain the compression cycle at P. Reverseflow through the scoop port 168, from outside atmosphere back into pipe161 is consequently materially reduced, and there is hence a materialnot outward and rearward flow of gases through the scoop port. Thisassures the desired pumping effect through the apparatus. Anotheradvantage may be recognized, in that it is known that the conventionalapparatus of this class, without the extension 166, tends to becomestarved for lack of air owing to poor reverse flow through the dischargeoutlet at high forward velocities. The present apparatus will not becomethus starved, because adequate air can always be obtained through theintake pipe, and a portion of this air is maintained in the extension166, to be supplied to the main pipe 160 during each reverse flowhalf-cycle in the pipe 160.

The gas discharge configuration is thus inthe nature of a scoop-port,utilizing the velocity energy of the gases participating in the velocityanti-node oscillation to effect their lateral deflection and discharge,and constitutes afrsarss an improved means for discharging hot gasesfrom the device with a minimum of sucking-in" of outside atmosphere atthis point and consequently with a net outflow effect.

In Figs. 19 and 20 the apparatus has a generally cigarshaped body 180,of either circular, elliptical, or lentiform cross-section, and has alongitudinal partition 181 extending laterally from side to side andfrom a point spaced a short distance from its nose end 182 to a pointspaced a short distance from its tail end 183. This partition may besupported as by struts or webs such as 184. It should be of high heatresisting material, and may be a slab of carbon. Air may be taken intothe nose by way of ports 186, controlled in this instance by reed valves186a. Fuel is introduced a nose-end combustion region 187 by fuelinjector pipe 188.

Midway of the length of the body 180, the body is formed, abovepartition 181, with an air intake port 190, this port 190 being in thenature of an arcuate slot extending circumferentially around the upperhalf of the body. A scoop 191 just outside the port 190 intercepts airwhen the apparatus is in forward motion, and directs it into the port190, and then into the body 180, as indicated by the arrows. This aircan be sufficient to support combustion, thus dispensing with ports 186and valves 186a, if desired. The partition 181 directs air through thecombustion zone before reaching the discharge.

Around the bottom half of body 180, midway of its length, there isformed a circumferentially extended hot gas discharge port 194, thisport being defined by outwardly and rearwardly flared member 195, andforwardly convergent deflector member 196, the latter having halfroundedge 197 facing forwardly in the apparatus below the partition 181. Thisedge 197 will be seen to be in position to intercept gas flow rearwardlyin the apparatus, below the partition 181, and the configuration is suchas to deflect this air flow outwardly and to eject it from the apparatusas indicated by the arrows.

In operation, combustion at the resonant frequency of the body 180 isestablished in the usual manner, with the result of the establishment ofa pressure anti-node P in the nose end of the body, a pressure anti-nodeP in the tail end of the body, and velocity anti-node regions V and Vmidway of the length of the body, above and below partition 181. In theregions V and V, gas oscillates in a longitudinal direction as indicatedby the arrows. Each time the gas flow in the velocity antinode region V,is in the direction from the nose towards the tail, air is taken in at190, and this air is useful to either air or support combustion and toelevate the mean pressure of the system. At the same time, the gas flowin the region V' will also be in the direction from the nose towards thetail, and a portion of this gas flow is intercepted by the edge 197, andejected from the apparatus by way of port 194. There is not muchtendency for air to be ejected from port 190 with gas flow in thereverse direction, because of intake port 90 being practically flushinside.

Fig. 21 shows an embodiment wherein a long, half wave pipe 200 has aquarter wave air intake pipe 201 opening into its head end 202, and isprovided with a closed end 203 at its tail. Fuel is injected at 204, anda spark plug is provided at 205.

Such a device, under pressure pulses generated at combustion zone 206,by igniting fuel charges thereat, resonates to set up a standing wavewith a pressure antinode P at the combustion region, a pressureanti-node P at the far end, adjacent end closure 203, and a velocityanti-node V midway of the length of the pipe. At the region V the gasoscillates at maximum amplitude.

Two hot-gas discharge pipes 207 and 208 are mounted in the wall of thepipe 200 near the velocity anti-node "region V, the pipe 207 having anopen intake end 209 facing toward the head end of the pipe 200, and thepipe 208 having an open intake end 210 facing toward cone supported bywebs 242.

the rearward end 203 of the pipe 200. Both pipes 207 and 208 dischargein a direction generally rearwardly of the apparatus. As will be seen,the pipe 207 intercepts gas from the velocity anti-node region when theflow is in the direction from the head end towardthe rearward end, andthe pipe 208 intercepts gas when the flow i in the reverse direction.Both pipes discharge gas from the system, and discharge takes place onboth half cycles of the alternating gas flow occurring in the region V.

Fig. 22 shows still another embodiment of the invention, being a twinburner pipe form having certain resemblance to the U-tube form of Fig.17, and having air intake provisions similar, in part, to the embodimentof Fig. 1. In general, the engine of Fig. 22 has two parallel burnerpipes 220, interconnected by a tail pipe fitting 221 at one end of theapparatus, and by a U-tube, or V-tube, valveless air intake means 222 atthe opposite end of the apparatus. Each burner pipe 220 has a forwardcombustion chamber 223, closed by forward head wall 223a, and a taperedportion joining the combustion chamber to reduced pipe section 224. Thetail pipe fitting 221 has two arms flange-fitted to the rearward ends ofthe two pipe sections 224, and is in the general form of a Y, the twoarms communicating with one another to form a continuous gas conduitconnecting the rearward ends of the two pipe sections 224, and the stemforming the tail pipe outlet. Gas traveling from one of these arms tothe other will be seen to make a turn. The fitting 221 has a rearwardopening to which is flange-fitted a reduced, rearwardly directed orificememher 226 through which products of combustion are etted.

The air intake assembly 222 is in the general form of a U-tube orV-tube, having two leg portions 230 connected into heads 223a, andjoined by a 180 return bend fitting 231, which, in the embodiment ofFig. 22, is somewhat pinched so as to reduce the radius of curvature ofthe bend. The two legs of fitting 231 are also preferably graduallyconstricted toward their forward end juncture, as shown. An air intakeport 234 opens into @the fitting 231 at its inner side, i. e., betweenits two legs, and the intake air is fed via the two legs'of said fittingand the pipes 230 into the combustion chambers 223.

Fuel for combustion may be introduced into the system in various ways,but is here shown as injected by means of fuel injectors 236 mounted inrings 237 placed between the ends of the fitting 231 and the adjacentends of the pipes 230. Thus fuel is injected into the air streamsentering the pipes 230 leading into the combustion chambers 223.

Fuel so introduced into the air intake system and conveyed thence to thechambers 223 is ignited in the latter, and ignition may be initiated bymeans of a spark plug 240 mounted in the side wall of one of thechambers 223. Once ignition has been initiated, a flame lingering in thecombustion chamber between explosions is available to burn successivefuel charges, and electric ignition is no longer required. To aid in theretention of this flame between explosions, a turbulizer land flameholder 241 is preferably employed at the head end of the combustionchamber, consisting in this instance of a small This cone afiords aprotected region wherein the flame is maintained in an attenuated statebetween explosions. It is found in practice that a spark plug need beused in only one of the two combustion chambers, since flame in oneofthe burner pipes will reach fuel in the other, and when the latter hasonce been exploded, flame thereafter resides bustion chambers 223through the described air intake means, fuel to be injected into thisair, and preliminary electric ignition to be provided a resonantstanding wave is established in the two burner pipes similar to thatdescribed in connection with Fig. 17, and need not be again described,excepting to note that a velocity anti-node region V appears in the tailpipe fitting 221, as indicated, and pressure anti-node regions P and Pappear at the head ends of' the combustion chambers 223; The combustioncycle is as in Fig. 17. The lengths of the two air intake paths from theintake port 234 to the combustion chambers 223 are of approximatelyone-quarter wavelength for a desired component of the resonant standingwave frequency of the twin burner pipes connected by the tail pipefitting 221, difference in temperature of gases in the air intake pipesystem and in the burner pipes being taken intoaccount. A resonantstanding wave accordingly is setup in the air intake pipe system, with avelocity anti-node appearing atV', in the general manner described inconnection with Fig. 1. Gas oscillation at resonant frequencyaccordingly occurs about the sharp bend of the air intake pipe system,opposite the air intake port 234.

Combustion gas discharge is effected from the system through the tailpipe discharge orifice 226, aided by cent'r'i'fugal force effects asexplained in connection with earlier described embodiments of theinvention, particularly that of Fig.- 1. Air intake into the valvelessair feed system 222 occurs inwardly through the air intake port 2-34; byreason of centrifugal force eflec'ts owing-to gas oscillation at V, as"described in connection with Fig. It isnoted, however, that the systemas shown in- Fig. 22 develops higher centrifugal force by reason of theradii of curiarent the 180 mn' of the pipe fittings 221' and 232 havingbeen minimized; The constriction of the pipefit'ting 231 more re ioncrate an intake port 234 contributes an additional air pumping factor byreason of Bernoulli enact. Thus the velocity of the oscillating gases inthe constricted region V is increased, and the pressure correspondinglydecreased, and this lowered internal pressure atV' improves air intake.

Fig. 22a shows a modi ication of the air intake system for the engine ofFig. 22, differing from the system of Fig. 22 only in that a modifiedair intake fitting 231a is used having a uniform cross sectional areathroughout, the provision for" increasing pumping by Bernoulli efiectthus being dispensed with in this case. Otherwise, the system" is thesamea'sthat' of Fig; 22. I v r Fig. 225 shows a modine'dtail pipefitting 221zz-foithe engine of Fig. 22 In Fig. 226, fragmentary rearwardend portions of the pipe sections 224 of the engine o f Fig. 22 areagain shown, and it will be understood that the engin forwardly of theflan es at the end portions of the pipes 2'24 may be ideniicai with thatshown Fig; 22.

The fitting 222a has, at the points of flange connection with therearwa'rds ends of pipes" 224, two rearwardly extending cylindrical legportions 255. Each of these merges or divides into two semi-cylindricportions 251 and 252, the former extending straight'rearwardly andterminating in a gas discharge outlet 251a, and the latter curvedthrough 90 rejoin the similarly curved member 252 of the other leg 25%.Thus the: rearward ends of the two burner'p'ipes' 225 are internallyconnected'by a U-tube configuration; while outside of the latter are twostraight, rearwardly directed gas' discharge pipes. It will be observedthat'the semi cylindr'i'c portions 251' and 25'2 have diametiic Walls254 and 2 55" merging to an apex at 255a to forma gas flow divider, andthat the wall portions 255 deflector turn the gas column through 180".

The velocity anti-node region is designated'by" the letter V and by theaccornpanyiiig double-headed arrow, which which represents the regionthroughout which it is particulariy enective. In other words, sonic gasoscillation owing to the resonant standing wave in the systeni is at thenecessarynear m'aximum throughout the extent of the gascolumn within thereach of the arrow. The sonically oscillatinggas column is split at 255,a portion being ejeeted to atmosphere through the pipe 251 undervelocity energy of the velocity anti-node, and a portion being deflectedor turned by the wait 2"5 and being then retained within the closedportion of the system. The latter portion of the gas column thusoscillates within and around the conduit connecting the burner pipes226, while the former is discharged straight reaivvardly. That portionwhich stays within and turns around the 180 condu'i't, as abovedescribed, and expands to fulfill most of the back-flow requirements forthe opposite pipe 224, thus minimizes cyclic back-flow into stacks 251.Accordingiy, outflow is more facilitated than is inflow, all due todividing the velocity anti-node gases at the discharge.

, A substantial number of exemplifications of the basic invention havenow been indicated for the purpose of mailing clear the full range ofthe invention. it is who understood, however, that no attempt has beenmade to be entirely exhaustive, and that numerous additional forms ofthe invention are possible and will occur to those skilled in the art.The inventionis accordingly to be regarded as broad in nature and to belimited only in accordance with the spirit of the appended claims.

I claim: p

1. A jet flow apparatus including a reasonant fluid conduit, pressurepulse generating rneansin a portion of said conduit for creatingperiodic pressure pulses in the fluid in" said conduit at a resonantfrequency of said conduit, whereby to create resonance insaid conduitwith pressure anti-node conditions therein adjacent said pressure pulsegenerating means velocity anti-node condition s there in, said conduithaving openings in the wall thereof definlng, respectively, a fluidinlet and a fluid outletto and from said conduit, at least one of saidopenings coinmunicatin'g with the interior of said conduit adjacent avelocity anti-node, the fluid-guiding surfaces of said conduit' adjacentsaid inlet and outlet openings having respect'ively differentconfigurations and being disposed relative to' the directionof fluidflow in said conduit adjacent said openings; soas to create a netpumping gradient in response to flow of fluid in said conduit over saidsurfaces andiir the direction inwardly of said inlet and outwardly of'said outlet.

2. The subject matter of claim 1, wherein the conduit has alongitudinaldeflection adjacent the region of said velocity anti-node,whereby to set up in the fluid traveling th'erealon'g a centrifugalforce component, and wherein said one opening is so located and disposedthat said centrifugai force component induces the desired fluid flow.

verselyof the conduit from the side thereof toward which gasesare'co'mpress'ed by the corresponding force component, and wherein saidfluid outlet opening communicates with said conduit at a point towardwhich gases are compressed by the corresponding centrifugal forcecomponent.

4. The subject matter of claim 1, wherein the conduit has a longitudinaldeflection adjacent the region of a velocity anti node, whereby to setup in the fluid travelingthere'along a centrifugal force component, andwhere in said fluid inlet opening communicates with said conduit in theregion of said longitudinal deflection and at a point spacedtransversely of the conduit from the side thereof toward which'gases arecompressed by said centrifug'al force component.

5. The subject matter of claim 1, wherein the conduit has a longitudinaldeflection adjacent the region of a velocity anti-node, whereby to setup in the fluid traveling therealong a centrifugal force component,andwherein concave longitudinal curvature in said region, and said fluidinlet opening communicates with said condult at a position spacedtransversely across the conduit from said region of concave longitudinalcurvature.

7. The subject matter of claim 1, wherein the fluid conduit has itsfluid outlet in the region of a velocity antinode and wherein theconduit has an internal surface of concave longitudinal curvature insaid region, and said fluid outlet opening communicates with saidconduit at said region of concave longitudinal curvature.

8. The subject matter of claim 1, wherein there are velocity anti-nodesin said conduit in the regions of said fluid inlet and outlet openings,and a fluid guiding and .deflecting wall portion of concave longitudinalcurvature in said conduit at each of said velocity anti-node regions,said fluid inlet opening communicating with said conduit at a pointspaced across the conduit from the corresponding wall portion of concavelongitudinal curvature, and said fluid outlet opening leading from saidconduit at a point adjacent the corresponding Wall portion of concavelongitudinal curvature.

9. The subject matter of claim 1, wherein said conduit is longitudinallyrounded and has a fuel combustion zone therein, and said means forcreating periodic pressure pulses comprises means for feeding fuel tosaid zone and periodically igniting said fuel to accomplish periodiccombustion at said zone at a resonant frequency of said conduit, saidperiodic combustion operating to establish' standing wave resonance insaid conduit with a pressure anti-node at a point half a wavelengtharound said conduit from said first mentioned combustion zone, andvelocity anti-node regions at half-way points between said pressureanti-nodes, said fluid inlet opening communicating with saidlongitudinally rounded conduit at the inner periphery thereof in theregion of one of said velocity anti-nodes, and said fluid outlet openingleading 1 point spaced transversely of the conduit from the side thereoftoward which gases are compressed by said centrifugal force component,and wherein said fluid inlet opening communicates with said conduit inthe region of said longitudinal deflection and at a point spacedtransversely of the conduit from the side thereof toward which gases arecompressed by said centrifugal force component.

11. The subject matter of claim 1, including a fluid deflecting wallmeans at a velocity anti-node region of the conduit for changing thedirection of at least a portion of the oscillating fluid, so as tocreate a pressure gradient through the fluid body inside the conduit,and said fluid inlet and outlet openings communicating with said conduitat diflerent pressure levels of said gradient to cause a net fluid flowthrough said openings and the in the wall portions of the conduit in theregion of said outlet opening are formed in a fluid dividing anddeflecting configuration such as to divide the oscillating fluid streamin the conduit adjacent the fluid outlet opening 29 into two divergentportions, one portion oscillating within the conduit and another portiondirected outward of said fluid outlet opening, whereby to inducedischarge of fluid from the conduit via said fluid outlet opening andconsequent inflow of air into said conduit via said inlet opening. I

13. The subject matter of claim 1, wherein the fluid outlet opening isadjacent a velocity anti-node, and wherein the conduit contains outletfluid path defining wall means configured and oriented to intercept andlaterally deflect a portion of the oscillating fluid stream in thevelocity anti-node region of the conduit, said outlet fluid pathdefining wall means discharging to the exterior of said conduit.

14. The subject matter of claim 13, wherein said outlet fluid pathdefining wall means comprises a scoop port having a month including afluid intercepting forward edge in said conduit in the path of a portionof the oscillatory fluid stream in said velocity anti-node region.

15. The subject matter of claim 1, wherein said conduit includes twoburner conduit sections and two air intake conduit sections, said airintake conduit sections joining one another at corresponding ends at anacuate angle, and each joining an end of one of said burner conduitsections at its opposite end, said pressure pulse means including ameans for creating periodic fuel combustion at the resonant frequency ofthe conduit in each of said burner conduit sections in a region adjacentthe juncture thereof with'the corresponding air intake conduit section,said air intake conduit sections being so proportioned that a velocityanti-node condition exists at the acute angled juncture thereof, andsaid fluid inlet opening comprising a port opening into the velocityanti-node region of air intake conduit sections from within the apex ofsaid acuate angled juncture.

16. The subject matter of claim 1, wherein said conduit has a velocityanti-node in the region of thefluid outlet opening, and wherein saidconduit has two legs leading into said velocity anti-node region, andjoined by a U-bend conduit section wherein the velocity anti-node ismaximized, said fluid outlet opening being divided into two parts, onefor each of said legs, each defined by a fluid discharge conduit havinga scoop port internally of the conduit and forming an extension of thecorresponding conduit leg, adjacent the juncture of said leg with saidU-bend conduit section, the oscillating fluid stream owing to saidvelocity anti-node being partially intercepted by said scoop ports andejected from the system via said discharge conduits.

17. A resonant fluid conduit of substantially ring shape having acombustion zone at one point therein, means for feeding fuel to saidcombustion zone and for periodically igniting said fuel to accomplishperiodic combustion at said zone at a resonant frequency of saidconduit, said periodic combustion operating to establish standing waveresonance in said conduit with a pressure anti-node at said combustionzone, another pressure antinode at a point half a wavelength around saidconduit from said first mentioned combustion zone, and velocityanti-node regions at half-way between said pressure antinodes, a fluidinlet opening into said conduit into the inner periphery thereof in theregion of one of said velocity anti-nodes, a fluid outlet leading fromsaid conduit from the outer periphery thereof in the region of the otherof said velocity anti-nodes, a second combustion zone at the secondmentioned pressure anti-node region, and means for feeding fuel to saidsecond combustion zone and for periodically igniting said fuel at phasedifierence from the periodic ignition at the first mentioned combustionzone.

18. Two resonant fluid conduits of substantially ring shape, eachhaving: a combustion zone at one point therein, means for feeding fuelto said combustion zone and for periodically igniting said fuel toaccomplish periodic combustion at said zone at a resonant frequency ofsaid conduit, said periodic combustion operating to establish standingwave resonance in said conduit with a pressure anti-node at saidcombustion zone, another pressure anti-node at a point half a wavelengtharound said conduit from said first mentioned combustion Zone, andvelocity anti-node regions at half-way points between said pressureanti-nodes, a fluid inlet opening into said conduit into the innerperiphery thereof in the region of one of said velocity anti-nodes, anda fluid outlet leading from said conduit from the outer peripherythereof in the region of the other of said velocity anti-nodes; thefluid discharge for one of said conduits being connected into the innerperipheral region of the other of said conduits at a point near thefluid outlet of said other conduit, and the fluid inlet for said otherconduit leading from an outer peripheral region of the first mentionedconduit at a point near the fluid inlet of said first mentioned conduit.

19. Two resonant fluid conduits of substantially ring shape, eachhaving: a combustion zone at one point therein, means for feeding fuelto said combustion zone and for periodically igniting said fuel toaccomplish periodic combustion at said zone at a resonant frequency ofsaid conduit, said periodic combustion operating to establish standingwave resonance in said conduit with a pressure anti-node at saidcombustion zone, another pressure anti-node at a point half a wavelengtharound said conduit from said first mentioned combustion zone, andvelocity anti-node regions at half-way points between said pressureanti-nodes, a fluid inlet opening into said conduit into the innerperiphery thereof in the region of one of said velocity anti-nodes, anda fluid outlet leading from said conduit from the outer peripherythereof in the region of the other of said velocity anti-nodes; thefluid inlet for one of said conduits being connected to the fluid outletfor the other of the conduits.

References Cited in the file of this patent UNITED STATES PATENTS2,523,308 Kemmer et al Sept. 26, 1950 FOREIGN PATENTS 188,642 GreatBritain Nov. 29, 1923 533,330 Great Britain Feb. 11, 1941

